Gaseous fuel mixer for internal combustion engines



H. w. .sMlTl-l` GASEOUS FUEL MIXER FOR INTERNAL COMBUST'ION ENGINES- Feb. 16, 1943.I

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Patented Feb. 16, 1943 GASEOUSFUELMIXER FORA f COMBUSTION ENGINES HaroldV Smith, Los Angeles, Calif., assigner to American Liquid Gas Corporation, Los-Angeles; Calif., a corporation of California Application September 30, 19740-, SerialNo. 359,063.Y

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This invention relates to fluid mixing devices and particularly pertains to a gaseous fuel mixer for internal combustion engines, and is a continuation in part of my copending application entitled Method and means of preparing a combustible fue Serial No. 224,718, filed August 13, 193s now issued as Patent No. 2,279,530 of" Apni 14, 1942. i

At the present time gaseous fuel, such as propane and butane, is used in internal combus: tion engines. When such fuel is used it is necessary to mix it with the proper proportion of air to make a combustible mixture which is then delivered to the engine. In view of the fact that internal combustion engines are built in a wide range of sizes it is difficult to obtain gaseous fuel mixers which are of suitable capacity for a particular engine, with the result that a large number of designs and sizes of carburetor or fuel mixer are required. It is the principal object of the present invention to provide a gaseous fuel mixing structure which is of composite character and makes it possible for a selection .of stock parts to be made whereby the mixer maybe mounted upon engines varying in fuel requirements with the assurance that the mixer asV assembled will supply fuel to the vengine properly without making it necessary for each individual engine to require a complete mixing or corporation unit for that particular engine, and theref fore making it possible for a few stock parts to be made which when selectively assembled will provide mixers of capacities covering a wide range of requirements. It is a further object of the present invention to provide a fuel mixer of the Venturi type in which it is possible to ob,-

tain an overload Venturi safety factor in a variaable orifice fuel-air mixer.

The present invention contemplates the provision of a gaseous fuel mixer having a valve structure assembled as a unit, said valve structure being interchangeably connected with a mounting flange and with Venturi throat sections of desired configuration.

The invention is illustrated by way of example in the accompanying drawing in which:

Figure 1 is a view in vertical section and elevation showing the application of the present invention to a manifold of an internal combustion engine.

Fig. 2 is an enlarged view in vertical section showing the fuel mixer.

Fig. 3 is aview in transverse sectionvshowing the details of construction of the fuel mixer as seen on the line 3--3 of Fig. I2.

Referring more particularly to the drawing, I0 indicates an engine-of the internal combustion type upon which a manifold structure "Il'fis mounted. rDhis manifold structure is of the type shown in my copending application aforesaid,`"of which this application is av continuation in part. A bolting flange I2 nis 1formed on'the',y manifold structure and around a gaseous fuel. inlet pas,- sage I3. Mounted upon the bolting. 'flange and secured by bolts I4 is the gaseous fuel mixerl I5 with which .the present,l invention is concerned. This gaseous fuel mixermrnalyY be usedV in c onjunction with a conventional'gasoline carburetor or may be used separately as shown in the drawing. I n View of the Yfact that engines are of different capacities it isnece's'sary to equip them with mixers of different capacities so'` farv as the throttle valve structurels concerned, while` utilizing an automatic main valve unit of a substantially common `vsize/for a large variety of engines.

The gaseous fuel mixer comprises a throttle valve portion lli` andan automatic valve portion I1. The throttle valve includes@ lower bolting flange I8 and a tubular throat portion I9, The tubular throat I9 has a lower cylindrical section '20 and an upwardly and outwardly flaring frusto- .conical portion'2 I. u I9 is fitted With a llting allge V2 2l receives screws 23. Thisbolting flange may t directly against a boltin'gange 24 of the housing of the automati'c'valve section I1 ormy have interposed between itand the iiange 22 the flange 26 of a Venturiwthroat element 21. Mounted in the cylindricallength 2,0 of the struc-` ture I6 is a buttery`valve`28 which may be moved to closed or opened positions in ,thethroat This valve is operatedby'the usual lever 29r carried upon the valve shaft 30; An adjusting lelement 3 I is secured onthe shaft bya set screw 32. This element carries arms 33 and '3g which may swing to encounter'astop pin 35 andlimit the movement of the valve in either -of two directions of rotation. The yalve lever 29 is of course connected with the :usual throttle control structure. The butteriiy'valve `28 is disposed Vat a point between the engine and the Venturi throat,

and also between 'thlengine 'and ,the air 'and' fuel valve structure. Y'This insures that an undisturbed columnV of Yair will be drawn into the mixer and around the valve uniform now.

The Venturi throat element 21 may be cast integral with the structur 'ormay be cast separately as shown in the drawing.Y When cast sepmately .the 'halting flange @menaitpessime The upper e'nd of the section of the bore 21 which extends downwardly as a part of the Venturi throat 21. It will thus be seen that during the initial period of downward movement of the air and fuel Valve the valve disc 59 and the valve 59 will cooperate with the walls of the cylindrical bore 21 to provide a mechanical metering action, and that when the air valve and the fuel valve move to VJtheir lowermost positions the disc 59 will be beyond the lower edge of the Venturi throat structure 21.

` At that time a free flow of gas and air will pass minates at its upper end in a bolting flange 38.V`

Formed centrally of the valve housing 25 is a tubular bearing element 39` which is carried by a transversely extending web 40. The central portion of the web below the member 39 is formed 'downwardly through the Venturi throat to be thereafter regulated by the throttle valve 28.

- In the initial stages of engine operation the fuel with a passageway 4| which terminates in an an-` f nular valve seat 42. The passageway 4| is sub- Y stantially cylindrical and communicates with a passageway 43 carried within the web and extending laterally thereof. The bowl portion 25 of the automatic valve housing is covered by an inverted bowl-shaped cover 44. This coveris fitted with a bolting flange 45 and receives screws 46 which secure the bolting flanges 38 and 45 together. The upper end of the cover 44 is formed with a central air opening 41 which-is surrounded by a cylindrical flange 48.* 'Ihis flange may be used to connect an air conduit with the b owl or to connect an air cleaner or the like. The bowl portion 25 and the b owl cover 44 form a chamber 49 within which an air valve member 50 is vertically reciprocable. The air valve member 50 has an inverted frusto-conical portion 5| and an upper portion of reduced diameter having an outwardly flaring curved face 52 by which incoming air may be directed outwardly and around the large diameter of the frusto-conical portion 5|. A hub 53 is formed at the upberend of the air valve element 50 and is pinned onta'l valve shaft 54 which extends downwardly through a central cylindrical counterbore 55 within the valve element 50. Thev counterbore is of a diameter to receive the upwardly'projecting tubular bearing element 39. A spring 56 Ais interposed between the upper end wall of the counterbore 55 and the end of the tubular bearing element 39. This tends to hold the valve element against an annular valve seatA 51 which circumscribes the air opening 41, at which timethe air valve element 50 will assume the position indicated in Fig. 3. The frusto-conicalportion' 5| of the air valve element maybe formed 'vth ducts 41 which permit a limited flow f 'air through the valve when the engine is idling. Mounted within the tubular extension 39 is a bearing bushing 58 through which the valve stem' 54 extends. At the lower end of the valve stem 54 is a fuel valve 59: 'Ihis valve is frusta-conical and in its upper position is drawn against the annular valve seat 42. Thus, the air valve 50 and the fuel valve 59 operate in unison as influenced by the spring 56 or engine suction. A valve washer 59 is carried on, the lower end-of the valve stem 54 and is -held yieldably by a spring and a nut 54 on the valve stem 54. latten--V tion is directed to the fact that therfuel valve element 59 has an upper frusto-conical portion and a lower cylindrical portion. 'Ihe cylindrical portion, as shown in Fig. 2 of the drawing, fits snuglywithin the passageway 4| when the valve is in its uppermost position, at which time the disc 59 will seat against the under face of the valve seat 42. The outside diameter ofthe disc 59 is substantially less than the inside diameter valve will perform the double function of regulating the inflow of fuel and regulating the flow of air. In order to control the feed of fuel dur- -ing idling times a duct 60 extends into the portion 5| of the bowl and communicates with a duct 6| which conducts the fuel around the fuel valve 59 and into the Venturi throat structure 21.V .The duct 6| is shown as having its'lower endin a position through valve seat 42 to-permit the valve washer 59 to close the opening when a positive fuel shut-olf is required. It will be evident that a flapper valve might be used if desired. A valve screw 62 adjusts the fuel volume.

It may be desirable to place a special adapter on the base of member 25 to permita gasoline carburetor to be used with the engine. In this event it is advisable to provide means for locking the automatic air fuel'valve open. In Fig. V3 such a device is shown as including a crank lever 65 mounted on a shaft 66. This shaft 'extends through a boss 69 in the wall of member- 44 4and may be operated by a lever 68 'from' a remote point of control. The crank lever rests at its free end upon shoulder V69 of the Vair valve50 and when swung to a desired setA position will hold the air valve 50 open while permitting the fuelfro'm a gasoline carburetor to pass'freely through the structure. In operation of the present invention the rating and fuel requirements of anr enginefare'ascertained, after which a throttle valve portion |9 is selected to meet the requirements of thegengine foruse with the automatic valve portiorrll. In addition various types of Venturi throat'structures may be used. The bolting flange Y22 `of the throttle valve housing'an'd thebo1tingv flange-24 of the automatic valve structure-are maintained at a common size so that these elements will be interchangeable. The bolting flange` |-8 at'rthe bottom of the throttle valve housing isi selected to accommodate the construction and design'y of a particular engine 'while the Venturi 'element is selected to produce a desired restriction-inthe air stream, or if desired, a structure with anin tegral venturi may be used. This insures that the mixing valve will function as a Venturi mixer during the full load range of engines suciently large to demand more fuel-air mixture' than is represented by the'normal movement-range of the interconnecting air-gas mixing valve.` -This is for the reason that the Venturi .action has little or no effect during light load operationsl of the engine, at which time `themechanical'mixing valve controls the volume of mixture. 3 f A It is also to be pointed out that when thestructure is assembled the mixer has been designed in 'a manner to insure that the mixing device will function on a great. variety of; engine seizes, and due to the interchangeability of parts it-is possible to adjust the air flow velocity and volurne in definite ratio to the fuel volume.- .As forex-v ample, the mixing valve can be arranged and adjusted to provide a lean mixture during light load range of operation of the engine as an economy feature with assurance that during the heavy load range the volume of air required will be sufficiently great to impart a velocity at the Venturi restriction and thereby give a rich mixture during the heavy load range of the engine. It will be appreciated that since lean fuel mixtures are destructive during the heavy load engine ranges the Venturi element will act as an overload safety factor.

When the structure is assembled it may be directly connected with a fuel supply through the extension member 43' within which the fuel passageway 43 occurs, after which suction of the engine as permitted by movement of the butterfly throttle valve 28 will tend to draw downwardly upon the air valve 54 and move the fuel valve 59 downwardly and in unison and automatically provide a desired mixture of air and gaseous fuel which is then drawn by suction into the engine.

It will thus be seen that the fuel mixture structure here disclosed provides a device which may be readily adapted and applied to engines of a great variety of sizes and fuel demands, and that by the use of a relatively few parts maintained in stock it will be possible to meet the requirements of a great many engines without making it necessary to maintain a large and expensive stock of completely assembled mixers.

While I have shown the preferred form of my invention as now known to me, it will be understood that various changes may be made in combination, construction and arrangement of parts by those skilled in the art without departing from the spirit of my invention as claimed.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A gaseous fuel mixer adapted to be applied to an internal combustion engine, comprising a housing, a fluid passageway centrally thereof, an air valve seat at the upper end of said passageway, a fuel valve seat at a point intermediate the ends of said passageway, an air valve adapted to move against the air valve seat, a fuel valve adapted to move upwardly toward a closed position with relation to the fuel valve seat, said valves moving in unison, yieldable means urging said valves to their seated positions, a Venturi throat structure disposed beneath said iiud valve seat and into the restricted area of which the fluid valve may move, means supplying fuel to said fuel valve and whereby the fuel and air will be mixed together and will pass downwardly through said Venturi throat'when the fuel and air valves are opened, and a throttle valve disposed in the air passageway between said Venturi throat and an internal combustion engine upon which the device is adapted to be mounted.

2. The structure of claim 1 including said Venturi throat having a restricted section of uniform diameter and along which the fuel valve moves.

3. The structure of claim 1 including said Venturi throat having a restricted section of uniform diameter and along which the fuel valve moves, the length of said throat portion being less than the length of travel of the fuel valve, whereby the fuel valve will move beyond said length and allow free flow of the gaseous fuel to the throttle.

4. The structure of claim 1 including said Venturi throat having a restricted section of uniform diameter and along which the fuel valve moves, an idling fuel duct leading from a fuel supply conduit, and valve means associated with the main fuel valve to positively close said duct when the main fuel valve is closed. y

5. A gas and air fuel mixer, comprising a main housing having an air inlet passageway at its upper end. and an air outlet passageway at its lower end, an air valve seat adjacent to the upper end of said passageway, an air valve therefor, a throttle valve at the lower end of said passageway, the Walls of said passageway tapering downwardly and inwardly, a fuel valve seat intermediate the air valve and the throttle valve and including a downwardly presented cylindrical bore forming an annular valve seat at its lower end and having a lateral fuel conduit communicating therewith at a point above said seat, a fuel valve adapted to move into said bore, said valve having an upper upwardly and inwardly tapered frustoconical length and a lower cylindrical length substantially fitting said'bore when in its full seated position, a Venturi throat section disposed below said seat and extending downwardly into the tapered throat of the main air passageway and having a central cylindrical bore into which the fuel valve may move, a connection between the air valve and throttle valve whereby they will move in unison and yieldable means tending to urge said valves toward their seated positions in opposition to suction action exerted by an engine connected to the lower end of the Venturi throat, said suction acting to draw air downwardly through the air valve and the fuel valve and to mix the air with the fuel admitted through the fuel valve.

HAROLD W. SMITH. 

